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Motocross Bikes

2018Yamaha YZ125

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The 2018 Yamaha YZ125 is a lightweight 125cc two-stroke dirt bike engineered for amateur and intermediate motocross riders seeking competitive performance. Known for its aggressive power delivery and nimble handling, this machine excels in technical terrain and tight sections where its compact 93.9kg frame becomes an advantage. The YZ125 remains a popular choice for riders developing their skills on the transition between smaller 85cc bikes and larger 250cc machines.

Capacity: 125.0 ccm
Engine: Single, two-stroke
Gearbox: 6-speed
Dry weight: 86.2 kg
Seat height: 975 mm
Power: 34.0 HP (25.0 kW)

⇄ Compare with another bike All model years

What’s new for the 2018 Yamaha YZ125

vs the 2017

Spec	2017	2018
Power	15.0 HP (11.0 kW)	34.0 HP (25.0 kW)
Front suspension	Speed-sensitive system inverted fork	KYBÂ® Speed-Sensitive System inverted fork; fully adjustable
Rear suspension	Fully adjustable single shock	KYBÂ® single shock; fully adjustable

Other years 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027

How it rides

Editorial estimate from the spec sheet - not lab tested

Off-road & trail97%

Cornering90%

City riding5%

Daily riding5%

Touring5%

Two-up0%

Track85%

Best for: Built purely for motocross racing and aggressive trail riding, not for commuting, road use, or casual leisure riding.
Built for: A raw, high-revving 2-stroke racer that rewards precise clutch and throttle control with explosive acceleration and razor-sharp handling on dirt.
Not ideal for: Not for beginners, road riders, passengers, or anyone wanting comfort, storage, or long-distance capability.

Scores are derived from the spec sheet using the same model across every bike, so they compare like for like.

Will it fit you?

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Your height

Inseam (optional)

Units

At 975mm, a rider of 68.9" with a 31" (estimated) inseam will not reach the ground comfortably on the 2018 Yamaha YZ125, with a cramped knee angle of around 85 degrees and an upright riding position.

Assumes about 30mm of suspension sag once seated. This is an approximation from category-typical geometry, not a measurement of this bike or of you - sit on one before you buy.

More bikes at over 900 mm — Sky High →

Find bikes that fit your height →

Full specifications

Engine

Capacity: 125.0 ccm
Power: 34.0 HP (25.0 kW)
Engine type: Single, two-stroke
Power/weight ratio: 0.3944 HP/kg (dry)
Bore x stroke: 54.0 x 54.5 mm
Compression: 10.7:1
Cooling system: Liquid
Fuel system: Carburettor
Starting: Kick
Ignition: CDI
Valves per cylinder: 1
Lubrication system: Premix

Transmission

Gearbox: 6-speed
Transmission type: Manual
Final drive: Chain
Clutch: Multiplate wet clutch

Dimensions & weight

Wheelbase: 1443 mm
Overall length: 2136 mm
Overall width: 828 mm
Overall height: 1295 mm
Seat height: 975 mm
Dry weight: 86.2 kg
Wet weight: 93.9 kg
Fuel capacity: 8.00 litres
Ground clearance: 366 mm
Oil capacity: 0.70 litres

Chassis & suspension

Frame: Semi-double cradle aluminium frame
Front suspension: KYBÂ® Speed-Sensitive System inverted fork; fully adjustable
Rear suspension: KYBÂ® single shock; fully adjustable
Front wheel travel: 300 mm
Rear wheel travel: 315 mm
Rake (fork angle): 26.0°
Trail: 109 mm

Brakes & wheels

Front brakes: Single disc. Hydraulic.
Front brakes diameter: 250 mm
Rear brakes: Single disc. Hydraulic.
Rear brakes diameter: 245 mm
Front tyre: 80/100-21
Rear tyre: 100/90-19

Other

Color options: Team Yamaha Blue

Compiled from manufacturer documentation and user contributions, corrected on an ongoing basis. Spotted something wrong? Tell us.

What changed, year to year

Differences highlighted

Specification	2008	2013	2018	2022	2027
Capacity	124 cc	124 cc	125 cc	125 cc	125 cc
Dry weight	86 kg	86 kg	86 kg	86 kg	86 kg
Seat height	998 mm	998 mm	975 mm	975 mm	980 mm
Fuel capacity	7.9 L	8 L	8 L	6.8 L	6.8 L

Illustrative - generated automatically by diffing the year records already on file, not a manufacturer-published changelog.

Rider Reviews

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MotorcycleDB Review

The 2018 Yamaha YZ125 is a powerful and reliable motocross bike that is perfect for riders of all skill levels. Its 125cc engine provides plenty of power for taking on challenging tracks, while its lightweight and agile design make it easy to handle. The bike's responsive suspension and precise handling make it a top choice for motocross enthusiasts who want a competitive edge on the track.

Overall, the 2018 Yamaha YZ125 is a top-performing motocross bike that delivers impressive power, handling, and reliability. Whether you're a beginner looking to improve your skills or a seasoned rider in need of a high-performance machine, the YZ125 is a great choice. With its sleek design and advanced features, this bike is a standout in its class and is sure to impress riders of all experience levels.